title: Protecting-group-free synthesis of chokols.
abstract: As a result of a combined theoretical and experimental study, we describe a two-step protocol for the preparation of an optically pure, multifunctional, cyclopentanic core shared by a number of natural products. This process is based on a hitherto unreported Ti(III)-mediated diastereoselective cyclization in which the hydroxy-directed template effect played by the Ti(III) species was found to be crucial for the stereoselective outcome of the reaction. The viability of this concept was confirmed with the first protecting-group free synthesis of three enantiopure chokols, namely, chokols K, E, and B.
authors.affiliation: Department of Organic Chemistry, University of Granada, Avda. Fuentenueva, 18071 Granada, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Pérez Morales
authors.forename: Julieta
authors.initials: J
authors.lastname: Catalán
authors.forename: Victoriano
authors.initials: V
authors.lastname: Domingo
authors.forename: José A
authors.initials: JA
authors.lastname: González Delgado
authors.forename: José A
authors.initials: JA
authors.lastname: Dobado
authors.forename: M Mar
authors.initials: MM
authors.lastname: Herrador
authors.forename: José F
authors.initials: JF
authors.lastname: Quílez del Moral
authors.forename: Alejandro F
authors.initials: AF
authors.lastname: Barrero